This section is from the book "British Wild Flowers - In Their Natural Haunts Vol2-4", by A. R. Horwood. Also available from Amazon: A British Wild Flowers In Their Natural Haunts.
Common and widespread, but obviously connected with the pursuit of agriculture, Groundsel is not represented in ancient deposits. In the North Temperate and Arctic Zones it is found in Arctic Europe and N. Africa, and it has been recently introduced into other parts in the Temperate regions of the globe. Groundsel is found in every part of Great Britain as far North as Scotland, and it is found in Northumberland growing at altitudes of 1000 ft., and in Ireland and the Channel Islands.
Groundsel is so familiar a plant and so cosmopolitan that one can hardly describe its habitat in brief, for it is found in a great variety of stations. It is essentially, however, a plant of cultivated ground, coming up in cornfields, turnip fields, in the farmyard, stackyard garden, and on every description of waste ground, being one of those domi-nant species that ousts all else in its neighbourhood. The plant is erect in habit. It may be downy or hairless, and is an extremely polymorphic species, numerous forms having been described by Professor A. H. Trow. The plant is succulent, with numerous fibrous rootlets. The stem is branched from the base, and gland-less, like the rest of the plant. The leaves are deeply divided nearly to the base, half-clasping, the lobes distant, oblong, blunt, variable, with acute, irregu-lar, coarse, unequal teeth, like the rachis and auricles. The lower leaves are stalked.
The flowerheads are few, small, drooping, hairless in a clustered raceme, oblong, cylindrical, and after flowering conical. The florets are all disk florets and yellow. The outer phyllaries are very short, and closely pressed, with black points, dark, egg-shaped to awl-like, many. There are usually no ligules. The fruit is ribbed, silky.
Groundsel is about a foot in height. It is to be found in flower all the year round. Propagation is effected by fruit, the plant being an annual and herbaceous. In the Alps it is perennial.
The capitulum is made up of 60-80 florets. They are all usually tubular, bisexual. The tube is 3 1/2 to 4 mm. long, the throat 1 to 1 1/2 mm. long. Honey rises in the tube as far as the throat, and can be readily obtained by short-lipped insects. The flowerheads are small, 4 mm. across, and are not generally rayed, so that they are not conspicuous, and few insects save Syritta, Pyrocoris, Halictus, Heriades, visit it. The plant is frequently self-pollinated. Hairs at the tip of the style sweep out the pollen grains, and they lie on the edge of the stigmas and fall on the inner surface when they separate. The plant is self-fertile. But fruit produced by cross-pollination has been shown by Bateson to be more vigorous than that derived from self-fertile plants.
Photo. B Hanley - Groundsel (Senecio Vulgaris, L.)
The fruit is provided with pappus, and adapted for wind dispersal. The achenes have short, closely-appressed hairs which secrete runners. It is largely a sand-loving plant, and addicted chiefly to a sand soil.
There are two minute fungi which are to be found upon it. Thielavia basicola and Coleosporium senecionis. The plant is galled by Urophora macrura. The other stage of the second fungus grows on fir trees. A beetle, Longitarsus holsaticus; 6 Hymenoptera, Colletes fodiens, C. daviesana, Andrena tridentata, A. denticulata. Nomada solidaginis, N. jacobaeae; 4 Lepidoptera, Silver Y-Moth (Plusia iota), P. pulchrina, Lime Speck (Eupithecia centureata), Wormwood Pug (E. absynthiata); a Heteropterous insect, Lopus sulcatus; and two flies, Titerica Westermanni and Chromatomyia albiceps, visit it.
Senecio, Pliny, is from senex, Latin for an old man, from its white pappus; and the second name (Latin) refers to its ubiquity.
Groundsel is called Bird Seed, Chickenweed, Chinchone, Grinning Swallow, Grinsel, Groundsel, Grunsel, Grundsel, Grunnishule, Sencion, Simson, Swichen. Grinning Swallow is a corruption of groundsel or grunswelge in Scotland, grundiewally, grundiewallow.
The Scottish Highlanders use it for the evil eye. Groundsel was said to have been the Virgin's bed. The plant has been used as a charm against ague. In the fifteenth century it was cultivated, and used for various complaints.
Essential Specific Characters:165. Senecio vulgaris. Stem erect, branched, glabrous or downy, leaves half-clasping, lobed, dentate, not viscid, flowerheads yellow, in drooping heads, rayless, outer phyllaries short, with black points.